This invention relates to propeller assemblies, and in particular, to a propeller assembly for a marine vehicle which incorporates a central hub having breakaway elements to prevent damage to drive system and the engine of the marine vehicle.
It is known to propel a marine vehicle utilizing a propeller assembly mounted on a rotatable drive shaft. The propeller assembly includes a plurality of propeller blades extending radially from a central hub. A motor rotates the drive shaft that, in turn, rotates the propeller blades propelling the marine vehicle through the water. Typically, the propeller assembly is constructed as a unit wherein the propeller blades and the central hub are mounted or removed from the drive shaft in unison. Alternatively, in order to reduce the time and costs associated with replacing the propeller blades, it has been contemplated to provide a propeller assembly for a marine engine wherein the propeller blades project from a propeller housing that is removable from a central hub.
By way of example, Chen, U.S. Pat. No. 5,967,751 discloses a marine propeller assembly that includes a central hub secured to the propeller shaft and having three or more axially extending keys on the outer surface thereof. A propeller housing includes an inner surface having three or more pairs of lobes for forming keyways that receive the keys of the central hub. A retainer disc is threaded on a propeller shaft and includes a plurality of angularly spaced ears for engaging with the lobes on the inner surface on the propeller housing in order to prevent the propeller housing from being disengaged from the central hub
While the advantages of a removal propeller housing are readily apparent, it can be appreciated that it is often highly desirable to retain the propeller assembly on the propeller shaft in such a manner as to prevent any unnecessary movement of the propeller assembly that may reduce the overall efficiency of the drive system of the marine vehicle. However, during such circumstances when the propeller blades engage a fixed object in the water such as a rock or the like, it may become necessary for the drive shaft of the marine vehicle to become disengaged from the propeller housing in order to prevent damage to the drive system of the marine vehicle. Consequently, it is highly desirable to provide a propeller assembly that disengages from the drive shaft in response to a predetermined force thereon.
Therefore, it is a primary object and feature of the present invention to provide a propeller assembly that may be simply and easily mounted on and removed from the drive shaft of a marine vehicle.
It is still a further object and feature of the present invention to provide a propeller assembly that may be mounted on the propeller shaft of a marine vehicle in such a manner as to prevent any unnecessary movement of the propeller assembly that may reduce the overall efficiency of the drive system of the marine vehicle.
It is still a further object and feature of the present invention to provide a propeller assembly that disengages from the drive shaft of the marine vehicle in response to a predetermined force on the propeller assembly.
In accordance with the present invention, a propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller shaft extends along an axis and terminates at a threaded end. The propeller assembly includes a central adaptor mountable on the propeller shaft for rotational movement therewith. The central adaptor defines a generally cylindrical outer surface having a plurality of circumferentially spaced recesses therealong. A generally tubular housing is slidable over the central adaptor. The propeller housing includes an inner surface and an outer surface. The bushing assembly translates rotational movement of the central adaptor to the propeller housing. The bushing assembly includes a bushing and an insert. The bushing has an outer surface which engages the inner surface of the propeller housing an inner surface having a plurality of circumferentially spaced, axially extending recesses therein. The insert also has inner and outer surfaces. The outer surface of the insert includes a plurality of circumferentially spaced, axially extending keys projecting radially outward therefrom. The keys projecting from the outer surface of the insert are receivable within corresponding recesses in the inner surface of the bushing. The inner surface of the insert includes a plurality of circumferentially spaced, axially extending keys projecting radially inward therefrom. The keys projecting of the inner surface of the insert are receivable within corresponding recesses and the outer surface of the central adaptor. A locking structure is mountable on the propeller shaft for retaining the propeller assembly on the propeller shaft.
The central adaptor may include an enlarge head formed on the first end thereof. The inner surface of the propeller housing includes a ledge formed therein. The enlarged head of the central adaptor includes a cavity therein. The cavity receives the locking structure when mounted on the propeller shaft. It is contemplated that a first side of a washer engage the ledge and a second side of the washer engage the enlarged head of the second adaptor in order to prevent removal of the propeller housing from the central adaptor. Alternatively, a first washer is positioned about the propeller shaft and is interconnected to the propeller housing at a first location adjacent the first end of the bushing assembly. A second washer is positionable about the propeller shaft at a second location adjacent the second end of the bushing assembly so as to capture the bushing assembly between the first and second washers.
Each key projects radially inward from the inner surface of the insert and disengages from the insert in response to a predetermined force thereon. As is conventional, the propeller housing includes a plurality of circumferentially spaced propeller blades extending from the outer surface thereof.
In accordance with a further aspect of the present invention, a propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller shaft extends along an axis and terminates at a threaded end. The propeller assembly includes a central adaptor mountable on a propeller shaft for rotational movement therewith. The central adaptor defines an outer surface having a plurality of circumferentially spaced recesses therealong. A generally tubular propeller housing is slidable over the central adaptor. The propeller housing includes an inner surface. A bushing assembly translates rotational movement of the central adaptor to the propeller housing. The bushing assembly includes a bushing and an insert. The bushing has an outer surface engaging the inner surface of the propeller housing and an inner surface having a plurality of circumferentially spaced recesses therealong. The insert has a plurality of circumferentially spaced keys projecting from the outer surface thereof and into corresponding recesses in the inner surface of the bushing. In addition, the insert includes a plurality of circumferentially spaced keys projecting from an inner surface thereof into corresponding recesses in the outer surface of the central adaptor. A first washer is positionable about the propeller shaft and is interconnected to a propeller housing at a first location adjacent the first end of the bushing assembly. A second washer is positionable about the propeller shaft at a second location adjacent the second end of the bushing assembly so as to capture the bushing assembly between the first and second washers.
The propeller assembly further includes a locking element mounted on a propeller shaft for retaining the propeller assembly on the propeller shaft. The central adaptor includes an enlarged head defining a cavity therein. The cavity receives the locking element mounted on the propeller shaft therein.
The inner surface of the propeller housing includes a ledge formed therein. The second washer is positioned between the ledge and the enlarged head of the central adaptor. As is conventional, the propeller housing includes an outer surface having a plurality of circumferentially spaced propeller blades extending therefrom. It is contemplated that each key projecting from the inner surface of the insert breakaway from the insert in response to the predetermined force thereon so as to allow the central adaptor to rotate independent of the propeller housing.
A propeller housing is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller shaft extends along an axis and terminates at a threaded end. The propeller assembly includes a central adaptor mountable on the propeller shaft for rotational movement therewith. A tubular propeller housing is slidable over the central adaptor. The propeller housing includes an inner surface. A bushing assembly translates rotation of movement of the central adaptor to the propeller housing. The bushing assembly includes a bushing and an insert. The bushing has an outer surface that engages the inner surface of the propeller housing and an inner surface. The insert has an outer surface operatively connected to the inner surface of the bushing and an inner surface. A breakaway element interconnects the inner surface of the insert and the outer surface of the central adaptor. The breakaway element allows the central adaptor to rotate independent of the propeller housing in response to a predetermined force on the breakaway element.
The propeller assembly may include a locking element mountable on the propeller shaft for retaining the propeller assembly thereon. The central adaptor includes an enlarged head defining a cavity therein. The cavity receives the locking element mounted on the propeller shaft therein. The inner surface of the propeller housing includes the ledge formed therein. A washer may be positioned between the ledge and the enlarged head of the central adaptor.
As is conventional, the propeller housing includes an outer surface having a plurality of circumferentially spaced propeller blades extending therefrom. The breakaway element may include a frangeable key extending along the inner surface of the insert. The frangeable key fractures in response to a predetermined force thereon. The central adaptor may include a recess in the outer surface thereof. The frangeable key extends into the recess of the central adaptor.